Thin panel surface mount microphone

Abstract

A sound and vibration sensor having a sealed cavity defined between a microphone element and structure panel and an area below the microphone element wherein the microphone element senses a change in acoustic pressure inside the sealed cavity caused by sound waves striking the structure panel.

What is claimed is: 
     
         1 . A sound and vibration sensor comprising:
 a housing;   a printed circuit board assembly (PCBA) including a microphone element, the PCBA being attached to a perimeter edge within the housing; and   an adhesive member having a first side adhered, in a sealed manner, to a perimeter edge of one end of the housing, the adhesive member having a second side adhered, in a sealed manner, to a structure panel; and   a sealed cavity defined between the structure panel and an area below the PCBA;   wherein the microphone element senses a change in acoustic pressure inside the sealed cavity caused by sound waves striking the structure panel.   
     
     
         2 . The sensor as claimed in  claim 1 , further comprising a ventilation path created by a leak channel in the PCBA between the sealed cavity below the PCBA and an area of the housing above the printed circuit board assembly and a vent in the housing above the PCBA. 
     
     
         3 . The sensor as claimed in  claim 2 , wherein the leak channel further comprises a circular cross-sectional area less than 0.4 mm in diameter and the vent further comprises a circular cross-sectional area less than 1.0 mm. 
     
     
         4 . The sensor as claimed in  claim 2 , further comprising a dense mesh layer covering the vent. 
     
     
         5 . The sensor as claimed in  claim 1 , wherein a portion of the structure panel that receives the second side of the adhesive member is thinned in comparison to surrounding structure panel. 
     
     
         6 . The sensor as claimed in  claim 5 , wherein an outer perimeter of the thinned structure panel is configured to match an outer perimeter of the adhesive member to receive the adhesive member in a fully sealed manner. 
     
     
         7 . The sensor as claimed in  claim 1 , wherein the adhesive member has a conformable foam core. 
     
     
         8 . The sensor as claimed in  claim 1 , wherein the structure panel is a vehicle body panel. 
     
     
         9 . The sensor as claimed in  claim 8 , wherein the second side of the adhesive member is adhered to a B-side of the vehicle body panel. 
     
     
         10 . A surface-mounted microphone module, comprising:
 a housing;   a printed circuit board assembly (PCBA) having an aperture, a perimeter edge of the PCBA is flush-mounted inside the housing at one end of the housing;   a microphone element mounted to the PCBA, the microphone element has an acoustic port aligned with the aperture of the PCBA; and   an adhesive member having a first side that is adhered, in a sealed manner, to an outer perimeter of the housing at one end of the housing below the PCBA, the adhesive member has a second side that is adhered, in a sealed manner, to a structure panel defining a sealed cavity;   wherein when sound waves strike the structure panel, surface vibration in a form of displacement in a direction perpendicular to the structure panel is induced and dynamically changes a volume of the sealed cavity thereby generating acoustic pressure that is proportional to a change in volume inside the sealed cavity, the acoustic pressure is sensed by the microphone element.   
     
     
         11 . The module as claimed in  claim 10 , further comprising a ventilation path created by a leak channel in the PCBA and a vent in the housing. 
     
     
         12 . The module as claimed in  claim 11 , wherein the leak channel is aligned with the vent. 
     
     
         13 . The module as claimed in  claim 11 , further comprising a dense mesh layer covering the vent. 
     
     
         14 . The module as claimed in  claim 10 , wherein an area of the structure panel that receives the second side of the adhesive member is thinned in comparison to surrounding structure panel. 
     
     
         15 . The module as claimed in  claim 14 , wherein an outer perimeter of the thinned structure panel is configured to match an outer perimeter of the adhesive member to receive the adhesive member in a fully sealed manner. 
     
     
         16 . The module as claimed in  claim 10 , wherein the adhesive member has a conformable foam core. 
     
     
         17 . The module as claimed in  claim 10 , wherein the structure panel is a vehicle body panel. 
     
     
         18 . The module as claimed in  claim 17 , wherein the second side of the adhesive member is adhered to a B-side of the vehicle body panel. 
     
     
         19 . The module as claimed in  claim 10  wherein the sealed cavity has a volume of less than 350 mm 3 . 
     
     
         20 . The module as claimed in  claim 10 , wherein the adhesive member has a thickness between 0.1 mm and 0.5 mm, the structure panel has a thickness between 0.1 mm and 2.0 mm, and an area of the structure panel enclosed by the adhesive ring is equivalent to a circular area of a diameter between 10 mm to 80 mm.